Multigrid tube



-Sept.6, 1938. s oE wE 2,129,016

MULTIGRID TUBE Original Filed June 16, 1933 Fig.3 Fig.4

- Jnvenfoh.

Patented Sept. 6, 1938 UNITED STATES PATENT OFFICE Original application June 16, 1933, Serial No.

676,039. Divided and this application Decemher 5, 1935, Serial No. 52,952. In Germany June 18, 1932 1 Claim.

Multi-grid tubes in which there are provided two control grids of equal effect (twin grids arranged in a plane or a cylinder), are already known. This application is a division of my prior 5 application 676,039, filed June 16, 1933.

According to the invention, these two grids are constructed so as to have increasing throughgrip in the direction of the length of the cathode. A form of embodiment of the grids in semi-cylin- 10 drical form according to the invention is illus- As shown, each grid consists of a wire bent to semi-circle-shaped sharp (Fig. 1) or meandrian (Fig. 2) zig-zags forming a semicylinder. The pitch of the zig-zags is increasing from one end to the other of the grids. Thus a variable throughgrip along the cathode is obtained and, as well known, a prolonged characteristic of the tube.

I claim:

A twin grid for electronic tubes consisting of two equal and symmetrically arranged semicylindrical grids, either of the grids consisting of a wire shaped in semicircle-formed zig-zags, the pitch of the zig-zags increasing along the axis of the grids.

SIEGMUND LOEWE. 

